The automatic film threading apparatus is primarily designed to be used with film processors of the type having a plurality of chemically-filled film developing and processing chambers arranged in pairs and in parallel rows. Each chamber has an upper port and a lower port where the film is caused to sequentially be transported through each of the chambers until the developed film exits at the upper port of the final chamber.
Most film processors have a film loading compartment where there is usually located a film input port, an exposed film spindle and a leader spindle having a first take-up reel loaded with leader film. Within each of the film developing and processing chambers is also located a contiguous strip of leader film where one end of the leader projects out of the first chamber and into the film input port in the loading compartment and where the other end is attached to a second leader take-up reel located near the upper port of the final chamber. The current method used to load the exposed film into the processor requires the following steps:
1. The exposed film is initially rolled onto a daylight film reel. The reel is then inserted into the exposed film spindle located in the film loading compartment.
2. The end of the exposed film is attached to the end of the leader film projecting from the upper portion of the first take-up reel. The attachment is accomplished by manually splicing the two ends of the respective films with non-corrosive staples.
3. The door on the film loading compartment is then closed, to avoid film exposure, and a first take-up reel switch is activated to wind the exposed film onto the first take-up reel.
4. After step three is completed the film loading compartment door is opened. The end of the leader film projecting from the first take-up reel, that now has the exposed film embedded at the core of the reel, is then spliced to the end of the leader film projecting out of the film input port. The splicing is accomplished by manually attaching the two ends of the respective leader films with non-corrosive staples. After the compartment door is closed the film processing commences when a second take-up reel switch is activated causing the leader film with the attached exposed film to be pulled through each successive developing and processing chamber.
5. At the end of the processing cycle the developed film, which is now wound on the upper portion of the second take-up reel, is transferred from the second take-up reel to a final viewing reel.
The above-described loading procedure is not cost-effective in terms of materials and manhours used. Because of the quantity of steps required for loading and processing the exposed film there is the possibility that the exposed film may be damaged and/or inadvertently exposed. Additionally, if the staple splice is not properly aligned the film may bind or twist within the processor causing the film to break.
A search of the prior art did not disclose any patent that read on the claims of the instant invention. However, the following U.S. patents are typical of the current state-of-the-art in film processors and film transport mechanisms.
______________________________________ U.S. PAT. NO. INVENTOR ISSUED ______________________________________ 4,131,356 Schmidt 26 December 1978 4,068,250 Anderson, et al 10 January 1978 4,045,809 Landers 30 August 1977 ______________________________________
The Schmidt patent discloses a film processor which includes a sheet transport having a finger pushing the rear edge of the film sheet. The fingers work in conjunction with edge guides that guide the edges of the , film along a path that leads down into a series of tanks and up and out of each tank in a loop over to the next tank, including a loop guide located at the end of each loop for guiding the film sheet around the loop.
The Anderson patent discloses a leader belt stabilizer for use on film processors. The belt is designed to maintain the desired orientation of the belt by removing any twists in the belt and straightening out the clip and the attaching arm immediately prior to the belt passing around the guiding rollers of the belt transport system.
The Landers patent discloses a film processor that uses magnetic carriages that mount releasable film grips that grip the film in a trailing relation to the carriages. The carriages are actuated by a magnetic element mounted for reciprocation within the developing chambers.